1. Field of the Invention
This invention relates to a color imaging device and method for adjusting color balance of an imaged still picture.
2. Description of the Related Art
In a camera device, pre-set color reproducibility is achieved by effecting white balance adjustment and black balance adjustment, even though the color temperature of an object differs from one light source to another.
In effecting white balance adjustment, a white object is imaged, and level adjustment is performed so that the signal levels of color signals in the white luminance point will be equal to one another. In effecting black balance adjustment, the black level of imaging signals is sampled by closing a lens shutter once, and adjusting the signal level so that the black levels of the respective color signals will be equal to one another.
It is therefore an object of the present invention to provide a color imaging device and a color imaging method whereby it is possible to effect color balance in a grey area intermediate between the black and white which has not been possible with conventional white balance adjustment.
It is another object of the present invention to provide a color imaging device and a color imaging method whereby it is possible to perform color balance adjustment in all grey areas including the black and white.
In one aspect, the present invention provides a color imaging apparatus including imaging means for imaging an object for generating a color imaging signal made up of a plurality of color signals, level balance control data generating means for generating level balance control data based on the relative relation between signal levels of the color signals, light exposure volume adjustment means for adjusting the light exposure volume of the imaging means, memory means for storing, in each light exposure volume adjusted by the light exposure adjustment means, the level balance control data generated by the level balance control data generating means, in association with signal levels of the color signals in each light exposure volume, and level balance control means for reading out the level balance control data associated with the color signals from the storage means, based on the signal level of each of the color signals, for controlling the signal level of each color signal. This enables color balance adjustment in a entire grey area between black and white which has not been possible to perform in conventional white balance adjustment.
In another aspect, the present invention provides a color imaging apparatus including imaging means for imaging an object for generating a color imaging signal made up of a plurality of color signals, pre-set area extraction means for sequentially extracting color imaging signals of portions representing images in a plurality of pre-set areas in a picture represented by the color imaging signals, level balance control data generating means for generating level balance control data based on the relative relation between signal levels of the color signals contained in the pre-set areas, storage means for storing the level balance control data in association with the relative relation of the signal levels of the color signals contained in the preset areas, and level balance control means for reading out the level balance control data from the storage means in association with the color signals based on the signal levels of the color signals for controlling the signal levels of the color signals. This enables automatic color balance adjustment in a entire grey area between black and white.
In still another aspect, the present invention provides a color imaging apparatus including imaging means for imaging an object for generating color imaging signals made up of a plurality of color signals, display means for displaying an image based on the color imaging signals, area designation means for designating a desired area in the image displayed by the display means, level balance control data generating means for generating level balance control data based on the relative relation between signal levels of the color signals constituting the color imaging signals corresponding to the area designated by the area designating means, storage means for storing the level balance control data in association with the signal levels of the color signals in the area designated by the area designating means, and level balance control means for reading out the level balance control data associated with respective color signals from the storage means based on the signal levels of the color signals for controlling the signal levels of the color signals. This enables color balance adjustment in a entire grey area between black and white by a simplified operation. BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic block diagram showing the configuration of an imaging system embodying the present invention.
FIG. 2 is a block diagram showing an illustrative structure of a color imaging device in the imaging system of FIG. 1.
FIG. 3 is a schematic block diagram showing an illustrative .configuration of a digital processor of the color imaging device shown in FIG. 2.
FIG. 4 is a block diagram showing the configuration of a LUT provided in the digital processor of FIG. 3.
FIG. 5 is a flowchart showing the method for adjusting the color balance in the imaging system of FIG. 2.
FIG. 6 illustrates the display contents of a display of an information processing apparatus in the imaging system of FIG. 2.
FIG. 7 illustrates the display contents of a display of the information processing apparatus shown in FIG. 6.
FIG. 8 is a flowchart showing the sequence of automatic adjustment of color balance in the imaging system of FIG. 2.
FIG. 9 is a flowchart showing the sequence of automatic adjustment of color balance in the imaging system of FIG. 2.
FIG. 10 illustrates the display contents of the display of the information processing apparatus shown in FIG. 6.
FIG. 11 similarly illustrates the display contents of the display of the information processing apparatus shown in FIG. 6.
FIG. 12 is a graph showing characteristics of the usual LUT in the imaging system of FIG. 2.
FIG. 13 is a graph showing characteristics of the LUT with negative-positive inversion in the imaging system of FIG. 2.
FIG. 14 is a flowchart showing another method for adjustment of the color balance in the imaging system of FIG. 2.
FIG. 15 is a flowchart for illustrating the sequence of formulating color balance correction data.
FIG. 16 is a flowchart for illustrating the sequence of white luminance level setting.